Space motion simulator system

ABSTRACT

The drive unit includes a vertically disposed drive shaft and a rotatable telescopic driven arm which is mounted for rotation about the drive shaft in a plane which intersects the drive shaft at a suitable angle. The gear train including elliptical gears is disposed between the drive shaft and the driven arm so that the arm will be rotated about the drive shaft at a variable rate. A stationary cam plate is disposed about the drive shaft and a cam follower on the telescopic arm controls the extension and retraction of the telescopic arm as the arm is rotated about the drive shaft. Meshing gears are provided on the stationary cam member and the rotatable driven arm to rotate the arm about its own axis while it is being extended and retracted by the cam. A driven member may be provided at the end of the driven arm which is also rotatable about its own axis.

[151 3,670,581 [451 June 20, 1972 United States Patent Holland [54]SPACE MOTION SIMULATOR SYSTEM [72] Inventor: Eldie H. Holland, Box 747,Athens, Ala. Pnmary Emmnep-Mmon Kaufman Attomey--Sughrue, Rothwell,Mion, Zinn & Macpeak ABSTRACT [22] Filed: Nov. 20, 1969 rotatabletelescopi about the drive shaft in a at a suitable an dispos the armwill be rotated about the A stationary cam plate is disposed about t camfollower on the telescopic arm contro M Mmm 455 m 7.33 P mflfi W N 6 :149 n m. E m A m m Q I a 9 m m a P u 0 u u S n. n m E 4 m m T A M m m n A3 S .m w. M. U N m n m m D w M m e n" In 8 m s m mm N .n R d4 m m u 0 8"& N 3 l 1 1. m CG. W Mn, s a A D3 Uh m m mm driven arm which is alsorotatable about its own axis.

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PMENTEDJum m2 SHEET 7 OF 8 Eat PATENTED N FIGYA SHEET 8 [IF 8 SPACEMOTION SIMULATOR SYSTEM CROSS-REFERENCE TO RELATED APPLICATION Thepresent application is a division of application Ser. No. 544,509 filedApril 22, 1966 and now Pat. No. 3,521,384 granted July 21, 1970.

The exploration of space requires the application of every discipline ofknowledge known to mankind. Consequently, there are serious needs for auniversal information system, or machine, that will serve as a problemsolving instrument for the scientist, engineer, and technician chargedwith solving the many interdisciplinary problems and creating thematerials and hardware required to explore space. Also, the universalinformation system must serve as an orientation and decision making toolto assist administrators and all other levels of management in arrivingat the most logical decisions when committing appreciable portions of anation's resources to space exploration. Further, the universalinformation system must be available to the news media and other groupscharged with the responsibility of keeping the lay public informed ofhow their tax dollars are being spent in the various space programs.Finally, the universal information system must serve teachers andstudents in colleges, universities, and high schools to train, motivate,and inspire succeeding generations to continue mankind s conquest ofspace.

The simulator of the present invention is a precision, twenty-year,three dimensional simulator system which displays as a function of timean earth-orbit space flight mission, an earthmoon space flight mission,an interplanetary space flight mission and the orbital and axial motionsof the nine planets of the solar system as they move around the sunscenter in their correctly oriented elliptical orbits at the propervelocities and equatorial orientations. The present system is portableand consists of a single main assembly which is capable of simulatingany of the above listed arrangements by means of a simple interchange ofparts within the main assembly. Also subsystem interchangeability withineach arrangement can be accomplished. The system can be updated toincorporate new knowledge of the planets and natural satellites and tosimulate various space flight missions.

The system is expected to become one of the basic instruments used bygroups within government, private industry, colleges and universities,and high schools engaged in research, development, design,and teachingin the fields of as tronomy and astronautics. It is significant that thesystem is a labor saving device which actually solves problems inastronomy and astronautics, especially celestial and spaceflightmechanics. The non-specialist, including the hardware designer, can usethe machine to quickly generate highly specialized data which isnormally supplied by those highly trained in the various specializedfields within astronomy and astronautics. Therefore, additional economycan be realized in our space exploration programs.

The system will also serve as an excellent management, news media, andlayman briefing tool for demonstrating current and proposed spaceexploration programs.

In addition to the various planets, satellites, and spacecrafts and themeans for driving these elements in their proper timed relation withrespect to each other, the present invention is also directed to theinstrumentation necessary for obtaining data from the system such as thedistance from the suns center to the spacecraft or planet's center,heliocentric orbital longitude, heliocentric orbital velocity, theintersection of the orbital plane of the planet or spacecraft with theorbital plane of the earth, the points of nearest and farthest distancesof the spacecraft or planet's center from the sun's center, the positionof the vernal equinox, the argument of perihelion, and the longitude ofperihelion. To obtain such data, scales are provided on the oblatespheroid which coincide with the orbital plane of each respective planetor spacecraft. The scales can be permanent or removable and navigationstar positions can be plotted on the spheroid in correct relationship tothe sun's center, planets, and spacecraft. The various instrumentationnecessary for obtaining the desired data is all mounted on a swiveledinstrument rack which is mounted symmetrical to the support stand andoblate spheroid and capable of swiveling 360 degrees thereabout. Therack is provided with a curved portion which has its center of radius atthe sun's center. The instrumentation includes an optical viewing andscale reading unit which is mounted for movement on the curved portionof rack along with a heliocentric ecliptic latitude meter whichautomatically computes and displays the number of degrees, minutes, andseconds of arc the viewed object is above or below the earth's orbitalplane. The optical viewing and scale reading unit and the heliocentricecliptic latitude meter are simultaneously positioned by means of a handwheel such that when the viewing unit is correctly positioned on anobject, the heliocentric ecliptic latitude is automatically computed anddisplayed on the latitude meter. The swiveled rack is also provided withheliocentric ecliptic longitude meter which automatically computes anddisplays the number of degrees, minutes, and seconds of arc the opticalviewing and scale reading unit is located from the vernal equinox. Theangle is measured in the earth's orbital plane and is computed as theinstrument frame is rotated about the support stand to correctlyposition the optical viewing and scale reading unit. Also mounted on theinstrument rack is a drive motor programmer which programs the runningtime of the system drive motor which drives the arrangements locatedinside the transparent oblate spheroid. The programmer can be set todrive the arrangements to any desired time period or position within atwenty-year range. A twenty-year time resolver is also mounted on theinstrument rack and computes and displays universal and ephemeris timeas each arrangement is driven through its motions inside the transparentoblate spheroid. Universal time is displayed in years, months, days,hours, minutes, and seconds. Ephemeris time is displayed in Julian daynumbers in increments to the fifth or sixth decimal place. Sidereal timecan also be displayed, if desired.

The present invention is directed to a space motion simulator systemwhich may be arranged to provide a heliocentricgeocentric earth-orbitspace flight simulator arrangement which will give the sun's center,earth-spacecraft motions, positions, distances, and velocities all as afunction of timefor any earth-orbit space flight mission consideredduring the twenty-year period.

The earth model will revolve around the suns center in its correctlyoriented elliptical orbit and at the proper velocities, and it willrotate about its polar axis at the proper rate and equatorialorientation. The earth model will be marked off in parallel lines ofgeocentric longitude and latitude to show the earths proper surfaceorientation at all times. Also, a line which coincides with the earthsorbital plane about the sun is included on the earth model to permitproper cross-hair alignment of the optical viewing and scale readingunit with the orbit scales on the transparent oblate spheroid. inaddition, surface detail and coloring is included on the earth model.

The launch site and tracking and communication stations can be correctlyplotted on the earth model to show the time and position of earth atlaunch and to show when each tracking and communication station can bein contact with the orbiting spacecraft. Also, other areas of interestcan be properly identified on the earth model to show the time andposition at which the spacecraft can monitor or survey the earth area inquestion.

The spacecraft model will be shown revolving around the earth model inits properly oriented circular or elliptical orbit. lt will travel atthe proper velocity or velocities and will be at the correct positionand distance from earth at all times during the earth-orbit mission. Forsome deep space earth-orbit missions, it is technically possible to showthe spacecraft model leaving the launch site and being maneuvered intoits prescribed orbit and the spacecraft will be time synchronized in itsprescribed orbit and maintain the correct time-positiondistance-velocityrelationship during the mission.

The spacecraft model can have motion about its center of mass to provideequal exposure time of the spacecraft's surface to the sun's rays and tocreate artificial gravity, if the spacecraft is manned.

The spacecrafi could be a manned orbiting laboratory, an assembly spacestation, or an unmanned scientific satellite. Also, more than onespacecraft can be included in the arrangement, if desired. If thespacecrafts follow different orbits, separate spacecraft drive unitsmust be included; however, if they have identical orbits but areseparated by some known angle, the same drive unit will drive thespacecrafts. An example would be six synchronous communicationssatellites spaced 60 degrees apart.

The heliocentric-geocentric earth-orbit space flight simulatorarrangement can be used to demonstrate past, present, and future mannedand unmanned earth-orbit space flight missions consisting of one or morespacecrafts. Past missions can be repeatedly simulated to assist in theanalysis and evaluation of data collected during the mission and thushelp determine if follow-up missions are required. Present missionswhich are already in flight can be simulated to demonstrate the missionsprogress to all concerned and to show simultaneously themotions,positions, distances, and velocities of the earth and spacecrafi as theearth revolves about the sun and rotates about its polar axis while thespacecraft orbits the earth. This will assist in the analysis andevaluation of data collected and processed during the mission. Withrespect to future missions, during the study and analysis phases ofdefiningtheearth-orbit mission objectives, the earth and/or space areasto be monitored or surveyed can be identified and studied in determiningthe surface and flight instrumentation and other experimental equipmentrequired to achieve the mission objectives.

All earth-orbits of interest can be simulated on the machine to assistin determining the following surface and flight systems requirements:

1. Mission period 2. Launch window 3. Propulsion, including guidance andcontrol (for the launch vehicle and orbit control) 4. Navigation 5.Surface and flight system communications and tracking 6. Spacecraftshielding for protection against solar and Van Allen radiation andmeteoroid hazards, as applicable 7. Life support (for manned missions)8. Landing site and alternate locations (if the spacecraft is to belanded).

9. Recovery systems and their deployment (if the spacecraft is to belanded).

Once the proposed mission objectives and requirements have beenestablished-the simulator will be used to demonstrate the mission to topmanagement and other interested groups during the course of obtainingfunding approval and mission go-ahead. After mission approval, thesimulator will continue to serve as an excellent orientation tool todemonstrate the mission to all levels of management, technical andadministrative groups, the news media, and laymen to assure that allhave a clear understanding of the mission objectives, requirements, andprogress during all phases of the mision.

It is significant to add that during the research, development, anddesign phases of the program, the simulator will be utilized, especiallyby the hardware designer and technician, to quickly generate veryspecialized data which must otherwise be supplied by those highlytrained in the various specialties within astronomy and astronautics,especially celestial and space flight mechanics. Therefore, the machineis a labor saving device and will inject additional economy into ourearthorbit space flight programs.

The simulator will be useful to the mathematics, physics, astronomy, andengineering departments within colleges and universities to: I

l. Actually solve problems in earth astronomy and astronautics,especially celestial and earth-orbit space flight mechanics,

2. Demonstrate the simultaneous heliocentric and geocentric motions ofthe earth and spacecraft 3. Demonstrate the surface and flight systemrequirements for manned and unmanned earth-orbit space flightoperations.

The present invention is also directed to a system which may be arrangedas a heliocentric-geocentric earth-moon space flight simulatorarrangement which will give the sun's center-earth-spacecraft-moonpositions, motions, distances, and velocities all as a function of timefor any earth-moon space flight mission considered during a twenty-yearperiod.

The launch site and world-wide tracking and communication stations canbe correctly plotted on the earth model to show the time and position ofearth at launch and to show when each tracking and communication stationcan be in contact with the spacecraft and moon. For-manned round-tripmissions, the primary and alternate landing sites can be plotted on theearth model to show their positions at all times during the mission.

The moon model will travel around the earth model in its correctlyoriented elliptical orbit and at the proper velocitiesif Also, the moonmodel will maintain its proper surface and equatorial orientation. Themoon model will be marked off in parallel lines of selenocentriclongitude and latitude to show the proper lunar surface orientation atall times during the earth-moon space flight mission. Further, surfacedetail and coloring is included on the moon model.

The fly-by area, or impact point, or spacecraft orbital plane and areato be surveyed, or the landing and launch sites can be correctly plottedon the moon model to show their positions during the mission.

The earth-moon spacecraft model will be shown leaving the earth andtravelling through space along its prescribed flight trajectory to themoon. Upon arrival at the moon, the spacecraft will fly-by, impact,orbit, or land on the moon in ac cordance with the mission plan. If themission is round-trip, the spacecraft will depart from the moon at theproper time and return to the earth along its planned flight path. Uponarrival in the earths vicinity, the spacecraft will go into anearthorbit, land, or fly-by; whichever the mission dictates. Duringflight, the spacecraft can have motion about its center of mass toprovide equal exposure time of the spacecrafts surface to the suns raysand to provide artificial gravity for crew members, if the spacecraft ismanned.

Therefore, the heliocentric-geocentric earth-moon space flight simulatorarrangement is capable of simulating a lunar mission in three dimensionwhile simultaneously displaying all pertinent space flight data as afunction of time. As with the earth-orbit space flight simulator theearth-moon space flight simulator can be utilized to simulate past,present and future missions especially to determine numerous surface andflight system requirements similar to those set forth above with respectto the earth-orbit simulator.

The space motion simulator system of the present invention is alsocapable of being used as a heliocentric-planetocentric interplanetaryspace flight simulator arrangement which will give the sun'scenter-departure planet-spacecraft-target planet motions, positions,distances, and velocities all as a function of time for anyinterplanetary space flight mission considered during a twenty-yearperiod. In such an arrangement, the planet models are driven about thesun's center in their correctly oriented elliptical orbits and at theproper velocities. Each planet model will rotate about its polar axis atthe proper rate and equatorial orientation. The planet models are markedoff in parallel lines of planetocentric longitude and latitude to showtheir proper surface orientation at all times during the space flightmission. Also, a line which coincides with the orbit plane of eachplanet about the sun's center is included on the respective model.Surface detail and coloring are shown on the planet models.

The launch station and world-side tracking and communication stationscan be correctly plotted on the earth model to show the time andposition of earth at launch and to show when each tracking andcommunication station can be in contact with the interplanetaryspacecraft and the target planet. For round-trip missions, the primaryand alternate landing sites. can be correctly plotted on the earth modeland thus display their locations at all times during the mission.

The fly-by area, or impact point, or orbital plane, or landing andlaunch sites can be correctly plotted on the target planet model to showtheir positions during the mission. The spacecrafi will follow itspredetermined interplanetary space flight trajectory and can havemotions about its center of mass to permit equal exposure time of thespacecrafts surface to the suns rays and to provide artificial gravityfor crew members, if the spacecraft is manned. The spacecraft will beshown leaving the earth and travelling through space along itsprescribed trajectory. On arrival at the host planet, the spacecraftwill fly-by, impact, orbit, or land on the planet; depending upon thedictates of the mission. If the mission is round-trip the spacecraftwill depart at the proper time and return home to earth where it willfly-by, go into earth orbit, or land, as the mission requires. In such asystem the spacecraft can be removed to allow the planets to be studiedseparately, if desired, just as one or more of a planet's naturalsatellites can be included in the arrangement. The same applies to theaforementioned earth-orbital and earth-lunar arrangements. It is alsotechnically feasible to simulate an interplanetary space flight missionwhich includes more than one host planet, that is, the spacecraft driveunit will include orbit plane changing maneuvers. As with the previousarrangements, it is possible to simulate a space flight mission in threedimension while simultaneously displaying all pertinent space flightdata as a function of time.

As with the two previous space flight simulator arrangements theinterplanetary flight simulator can be utilized to simulate past,present and future missions especially to determine numerous surface andflight requirements similar to those set forth with respect to theearth-orbit simulator.

Another arrangement which may be displayed on the space motion simulatorsystem of the present invention is a solar systemheliocentric-planetocentric motion simulator arrangement. Such anarrangement gives the simultaneous motions, positions, distances, andvelocities all as a function of time for each one of the nine planetsduring a twenty-year period. The planets are driven about the sunscenter in their correctly oriented elliptical orbits and at propervelocities. In addition, the planets rotate about their polar axes atthe proper rates and correct equatorial orientations. Each planet modelis marked off in parallel lines of planetocentric longitude and latitudeto show the planet's proper surface orientation at any time. Also, aline is included on each planet model which coincides with the planetsorbit plane about the sun's center. Surface detail and coloring isincluded, consistent with each planet model size and current knowledgeof the planets. Furthermore, the correct surface to surface distancesbetween adjacent planets is maintained. The solar system simulator is alabor saving device because it computes and displays very specializedplanetary data which must otherwise be computed by those highly trainedin astronomy, especially celestial mechanics. This is significant in thefield of astronautics because the machines shows the planets in motionand simultaneously makes a planetary data available to thenon-specialist in astronomy for use in the study and implementation ofmanned and unmanned space flight missions. For example, a spacecraftunit may be included in the arrangement to simulate the mission of aninterplanetary astronomical observato The solar system simulator can beutilized to plan and implement ground based optical, radio, and radardeep space observation programs. The position of each observing stationcan be correctly plotted on the earth model to show when each stationcan observe a particular planet or sky area. This will be especiallyhelpful in planning and coordinating the activities of the variousobserving stations participating in national and internationalcooperative astronomy and astronautics programs. The planet models arealways shown in their correct positions and moving at their propervelocities, so that the simulator will be useful in setting upperturbation equations required in the computation of planetaryephemerides.

Therefore, the space flight simulator system of the present inventionprovides a compact portable unit which may drive a plurality ofinterchangeable planets, satellites, and spacecrafts to their properpaths with respect to each other and to the suns center.

Other features of the invention will be pointed out in the followingdescription and claims an illustrated in the accompanying drawings,which disclose, by way of example, the principles of the invention andthe best mode which has been contemplated of applying those principles.

In the drawings:

FIG. 1 is a perspective view of the simulator system arranged as aheliocentric-geocentric earth-orbit space flight simulator,

FIG. la is partial sectional view showing the fine adjustment means,

FIG. lb is a detailed view of the vertical drive on the instrument rack,

FIG. 2 is a perspective view of the simulator system arranged as aheliocentric-geocentric earth-moon space flight simulator, v

FIG. 3 shows a perspective view of the simulator system arranged as aheliocentric-planetocentric interplanetary space flight simulator,

FIG. 4 is a perspective view of the simulator system arranged as a solarsystem heliocentric-planetocentric motion simulator,

FIG. 5 is a schematic view of a typical-elliptical or circular orbitdrive unit,

FIG. 5a is a partial sectional view of the left hand end of themechanism shown in FIG. 5 and indicated therein by the legend, FIG. 5a,

FIG. 5b is a partial sectional view of the right hand end of FIG. 5indicated therein by legend, FIG. 5b,

FIG. 6 is a detailed plane view of the spline shaft connection shown inFIG. 5b,

FIG. 7 is a schematic view of the spacecraft telescoping drive unit,

FIG. 7a is a partial sectional view of the left hand side of themechanism shown in FIG. 7 and designated therein by the legend, FIG.7a",

FIG. 7b is a partial sectional view of the right hand sideof FIG. 7 anddesignated therein by the legend, FIG. 7b",

FIG. 8 is a partial sectional view of the slip ring construction shownin FIG. 7a,

FIG. 9 is a side elevational view of a spacecraft orbiting drive unitadapted to be used in conjunction with a spacecraft telescoping driveunit, and

FIG. 10 shows a schematic view of the gear track path on the split gear.

Referring now to FIG. 1, the numeral 10 designates in general the spacemotion simulator system of the present invention. The particulararrangement employed within the transport oblate spheroid 20 in FIG. I,is that of a heliocentric-geocentric earth-orbit space flight simulator.The transparent oblate spheroid 20 is mounted symmetrical to the sunscenter which is indicated by the dot 35 and encloses the internalarrangements as shown in FIGS. 1-4. The spheroid 20 is mounted upon thesupport stand 22 which houses the system drive motor and central driveshaft which provides angular input to the servo box 69 and drives thearrangement shown inside the oblate spheroid. The support stand alsoserves as a mounting column for the swiveled instrument rack, instrumentgears and servo box. The spheroid 20 is provided with an access dome 24which may be removed to enable the arrangements within the spheroid tobe changed. The ecliptic plane, which is the imaginary plane in whichthe earth orbits the sun, intersects the spheroid along the line 26. Thespheroid may be provided with scales along the line 26 which may eitherbe engraved or embossed into the material of this spheroid or may beapplied thereto by means of a tape member or may be painted thereon.Navigation star positions and the position of the vernal equinox canalso be plotted on the spheroid in correct relationship to the sun'scenter, planets and spacecraft but have not been shown on thisparticular model. A plurality of scales may be placed on the oblatespheroid to coincide with each orbital plane of each respective planetor spacecraft. These scales may be utilized to show the following datafor each planet and interplanetary spacecraft:

l. Distance from the suns center to the spacecraft or planet's center.

2. Heliocentric orbital longitude 3. Heliocentric orbital velocity.

4. The intersection of the orbital plane of the planet or spacecraftwith the orbital plane of the earth. 5. The points of nearest andfarthest distances of the spacecraft or planes center from the sun'scenter.

6. The position of the vernal equinox.

7. Argument of periphelion.

8. Longitude of periphelion.

Extending upwardly within the transparent oblate spheroid 20 is astationary cylindrical support column 28 having an attachment flange 30which may be secured to the support plate 23 by any desirable means. Thesupport plate 23 is secured to the uppermost end of the support'stand22. The drive shaft from the drive motor (not shown) which is locatedinside the support stand extends upwardly through the support column 28which is hollow and engages the drive unit 32 which is locatedintermediate the ends of the support column 28. Located above the driveunit 32 is a transparent transtage 34 which is a spherical memberinserted within the length of the tube 28. This is to enable the viewingof a .5 mm diameter sphere 35 which designates the sun's center andwhich is em bedded in a transparent section of the drive shaft. Half ofa common coupling 36 is located at the uppermost end of the supportcolumn 28 to provide connecting means for additional drive units similarto the drive unit 32, thus providing interchangeability with the systemshown in FIG. 2.

The drive unit 32 is adapted to provide the power take-off for movingthe earth about the suns center, as well as providing the power forturning the earth about its axis and for rotating a satellite, eithernatural or artificial, about the earth. Extending outwardly from thedrive unit 32 is a hollow telescope drive tube 38 which is provided withan equatorial orientation unit 40 to which the drive connections for aparticular planet or spacecraft may be coupled. The drive unit 32, tube38 and unit 40 may be similar to the drive shown in detail in FIGS. aand 5b. Extending outwardly from the unit 40 are a plurality of supportlinks 41 which are connected to and support a transparent geocentricglobe 44. Mounted within the globe 44 and concentric therewith is amodel of the earth 52 which is supported on and driven from the unit 40by means of a plurality of tubes and joint members having a drive shaftlocated therein and generally designated by the numeral 42. The gearingwithin the unit 40 and the drive shaft within the tubing 42 provide thenecessary drive arrangements for rotating the earth about its own axiswhile maintaining the proper equatorial orientation. The transparentgeocentric globe 44 may be provided with a plurality of parallel lines46 of right ascension and declination. Parallel lines of geocentriclongitude and latitude may be placed upon the surface of the earthmodel, if desired. Also scales which coincide with the spacecraftsorbital plane can be included on the globe to show the spacecraftsdistance from the earth, orbital velocity, geocentric right ascensionand declination, apogee and perigee points, and the ascending anddescending nodes. The line 48 on the globe 44 designates the eclipticplane. The globe 44 is provided with an access lid 50 similar to theaccess dome 24 on the transparent oblate spheroid to enable theinterchangeability of the elements within the globe.

Mounted on the earth support tube 42 adjacent the earth model 52 is aspacecraft drive unit 54 which may be similar in construction to thedrive unit 32. The drive train 57 for the spacecraft 56 is provided witha telescopic connection since the orbit desired, in this case, will bean elliptical orbit about the earth. A telescopic drive arrangementsimilar to 38 is provided. The drive train 57 enables the spacecraft torotate about its axis as the spacecraft rotates about the earth 52.

Extending outwardly from the base 22 and mounted thereon for 360 degreemovement thereabout is a horizontally extending frame 58 which issecured to plate 59 which in turn are rotatably mounted on the supportstand 22. t

The manual vernier adjustment hand wheel 61 operates a gearingarrangement which causes the "central drive shah" to rotate when thedrive motor is not running. The manual vernier adjustment is utilized toexactly position anyarrangement inside the transparent oblate spheroid20. If the drive motor programmer does not cause the particulararrangement inside the transparent oblate spheroid to stop at thedesired time or position as indicated on the twenty-year time resolver68, or as viewed through the optical viewing and scale reading unit 73,the hand wheel 61 can be pressed forward and rotated to cause thecentral drive shaft to rotate until the exact time or position isachieved.

Hand wheel 61 (FIGS. 1 and la) is attached to shaft 62 which is mountedin the frame for axial sliding movement. On the opposite end of shaft 62is attached gear 63 which meshes with rotatable gear only when handwheel 61 is pressed forward. Friction gear 27, which is always incontact with rotatable gear 60, is mounted on shaft 29 which extendsthrough the support stand wall 22. Gear 31 is mounted on the oppositeend of shaft 29 from friction gear 27. Gear 31 always meshes at 90 withgear 33 which is mounted on the central drive shaft 25, Therefore, whenhand wheel 61 is pressed forward and rotated, the central drive shaft iscaused to rotate by action of the gear arrangement described. The secondring gear 60 is also fixedly attached to the support stand 22 and is inmeshing engagement with a gear 66 secured to shaft which is rotatablyjoumaled in the horizontal frame 58. The outer end of the shaft 65 isconnected to the heliocentric ecliptic longitude meter 67 which issecure on the horizontal frame 58. As the horizontal frame 58 rotatesabout the stand 22 the shaft 65 will be caused to rotate and the motionthereof will be imparted to the longitude meter and the exact positionof the frame with respect to the stand will register on-the meter indegress, minutes, and seconds.

Also mounted on the frame 58 adjacent the longitude meter 67 is atwenty-year time resolver 68. The twenty-year time resolver computes anddisplays universal and ephemeris time as each arrangement is driventhrough its motions inside the transparent oblate spheroid. The rotationof the main drive shaft within the support column 22 is transmitted tothe servo box 69 secured to the support stand 22. The servo box 69converts the motion of the drive shaft into electrical signals which aretransferred to the twenty-year time resolver 68 by means of themulticonductor cable 70. The signals received by the time resolver 68are converted into universal time which may be displayed in years,months, days, hours, minutes and seconds. Ephemeris time may bedisplayed in Julian day numbers in increments to the fifth or sixthdecimal place, it is also contemplated that sidereal time can bedisplayed, if desired.

Also mounted on he frame 58 adjacent the longitude meter 67 is the drivemotor programmer 55 which programs the running time of the system drivemotor which drives the arrangements located inside the transparentoblate spheroid.

The programmer can be set to drive the arrangements to any desired timeperiod or position within a twenty-year range.

The time resolver 55 is connected to the drive motor by means of thesame wire 70 that connects the time resolver to the servo box. The wire70 may be provided with a spring take-up reel intermediate the endsthereof so that the excess wire necessary for the 360 degree rotation ofthe'frame 58 about the stand 22 may be neatly stored. It is alsocontemplated that a slip ring connection between the frame and thesupport stand could be utilized to provide the electrical connectionsbetween the time resolver and drive motor programmer with the servo boxand drive motor respectively.

Extending upwardly from the horizontal rack 58 is a vertically extendingcurved rack member 71 which has for its center of curvature the sunscenter 35. The vertical rack 71 is provided with screw thread 71 and across frame 72 is adapted to be screwed up and down the vertical rack.Secured to the cross frame 72 for movement therewith are an opticalviewing and scale reading unit 73 and a heliocentric ecliptic latitudemeter 74. A hand wheel 75 is mounted on the frame 72 and is adapted todrive a nut 75 which is mounted for rotation on the cross frame 72 andwhich travels along the threads 71 on frame 71 so as to move the frame72 up and down with respect to frame 71. One of the vertical uprights ofthe frame 71 may be provided with an elongated gear rack 71" recessedwithin the threads 71' and a rotatable gear member 74 extendingoutwardly from the latitude member 74 is in meshing engagement with therack 71" so as to translate the relative motion between 71 and 72 into areading on the meter in degrees, minutes, and seconds.

All of the various meters, time resolvers, motor programmers, andoptical viewing units are available on the open market and since thepresent invention is not concerned with the detailed workings of thesedevices, it is not necessary to go into a greater detailed descriptionof these elements.

Turning now to FIG. 2, we see that the system has been arranged as aheliocentric-geocentric earth-moon space flight simulator. The majorportion of the support stand 22 and the movable meter supporting framework has been substantially removed since it is exactly the same and theonly differences being in the arrangement within the transparent oblatespheroid 20. The lid 50 for the geocentric globe 44 has been removed, aswell as the earth model 52, the satellite 56 and the drive arrangement54,57 therefor. In FIG. 2 an auxiliary support column 76 is connected tothe coupling unit 40 on the outer end of the drive tube 38. Intermediatethe ends of the auxillary support column 76 is located the geocentricmoon drive unit 79 which is adapted to drive the moon 82 about thereduced scale earth model 78. The drive unit 79 also rotates the moon 82about its axis through the drive train 80 and 81 so that the samesurface of the moon will always be presented to the earth. Thetelescopic drive unit 80 is similar to the drive unit 38 and enables themoon to follow an elliptical path about the earth. The earth 78 isrotated about its axis and the axis is maintained at its properinclination by means of the drive unit 77 secured to the uppermost endof the support column 76. A detailed description of the mechanism withinthe various drive units will be discussed later.

A spacecraft drive unit has been added to the uppermost end of thesupport column 28. A support column extension 83 is secured to thecommon coupling 36 and is provided at its upper end with an earth-moonspacecraft heliocentric orientation unit 84 for maintaining constantspacecraft drive unit geocentric orientation. The unit! also impartsrotary motion to the spacecraft geocentric drive unit 86. Theheliocentric drive portion of unit 84 shall be similar to theheliocentric drive portion of the earth unit 32. Extending outwardlyfrom the drive unit 84 is a telescopic drive tube 85 similar to thetelescopic tube 38. On the outer end of the drive tube 85 an earth-moonspacecrafl geocentric drive unit 86 is mounted. The design andorientation of this unit is to be determined by the specific missionunder consideration but is basically a unit as shown in FIG. or FIG. 7.The drive for the spacecraft 88 is provided through the drive trainflwhich also incorporates a telescopic drive. The general arrangementshown in FIG. 2 could also be used to simulate an aerospace shuttlecraftfor round trips between the earth and an orbiting laboratory orassembling space station. Thus, it is seen that in FIG. 2 the spacecraft 88 may take off from the earth and follow the proper trajectoryoutwardly to the moon 82 and return to earth 78 if the mission is roundtrip. In addition to the parallel lines and geocentric right ascensionand declination shown in the globe 44, scales which coicide with therespective orbit planes of the moon and spacecraft can be included onthe globe to give the moon and spacecraft distance from the earth,orbital velocity, geocentric right ascension and declination, apogee andperigee points, the ascending and descending nodes, and the distancefrom the spacecraft to the moon.

With respect to the arrangement shown in FIG. 3, we see that everythinghas been replaced within the transparent oblate spheroid 20 that waspresent in either FIGS. 1 or 2. A new support column 92 having the sunscenter indicated by the dot 93 has been mounted on the top plate 23 ofthe support stand 22. Intermediate the plate 23 and the suns center 93an earth drive unit 91 and an additional planet drive unit are mounted.The drive unit 90 could be arranged to drive any of the planets in thesolar system and for the purposes of this example, the planet 103 willbe considered as the planet Mars. The upper end of the support column 92is provided with a common coupling 94 to which is secured a spacecraftheliocentric drive system unit 95. The drive unit 95 is similar to thedrive unit shown in FIG. 7 but the exact design and orientation thereofwill be determined by the specific interplanetary flight trajectoryconsidered. The motion of the drive unit 95 is imparted to thespacecraft 97 by means of the telescopic drive connection 96 similar tothat shown in FIG. 7. The earth model 100 is rotated about its own axisand maintained at the proper inclination by means of the drive unit 99secured to the outermost end of the telescopic drive connection 98,which in turn is connected to the earth drive unit 91 on the mainsupport column 92. Likewise, the planet Mars is rotated about its axisand the axis is maintained at the proper inclination by means of thedrive unit 102 mounted at the outermost end of the telescopic driveconnection 101, which in turn is connected to the planet drive unit 90.The drive unit 102 could be connected directly to the telescopic drivearrangement 101 or an intermediate drive tube as shown in FIG. 3 couldbe interposed therebetween depending upon the space requirementsdetermined by the shape of the transparent oblate spheroid. Thetransparent oblate spheroid 20 is provided with the lines 26 and 89which represent the orbital planes of earth, Mars and the spacecraft.Once again, scales may be located along these lines to show distances,velocities and the various positions of the planets and spacecrafts withrespect to each other and the suns center. Also, scales can be projectedagainst the upper portion of the spheroid which will give the departureplanet to spacecraft distances; spacecraft to target planet distancesand the distances between the departure planet and target planet for alltimes during the space flight mission. In this arrangement, thespacecraft 97 is adapted to take off from the earth 100 and follow theproper trajectory through the intervening space to the planet Mars 103,and return if the mission is round trip while the two planets followtheir proper paths through space. It is obvious for trips to planetscloser to the sun, the earth would be the outermost planet. Also,additional heliocentric planetocentric drive systems may be added to thesupport column to simulate by-planet missions or Venus swing-by Marsmissions.

Turning now to the arrangement in FIG. 4, we see that once again anentirely new unit has been mounted within the transparent oblatespheroid which will simulate the relative positions and motions of thenine planets with respect to each other and the sun s center. Thetransparent oblate spheroid 20 is provided with markings 104 whichdesignate the orbit planes of each of the planets. 1f the scale readingsalong the lines 104 are permanently etched into the transparentspheroid, it is obvious that the spheroid would also bereplaced whenchanging from system to system. However, the scale readings and otherorbital markings can be included on a thin film transparent materialwhich can be accurately attached to the spheroid, if desired. Secured tothe upper surface of the plate 23 is a support column 116 upon which arelocated the planet drive units 115, one for each of the nine planets.The uppermost end of the support column 116 has the center of the sun105 secured thereto. Each of the drive units are similar to the driveunits 32, 91 and 90 shown in the previous embodiments and described morefully in detail in FIG. 5. The 9 planets being driven in their properpaths about the sun's center 105 are Mercury 106, Venus 107, Earth 108,Mars 109, Jupiter 110, Saturn 111, Uranus 112, Neptune 113 and Pluto114.

FIG. shows the schematic view of a typical planet drive arrangement fromthe main support column 120 having a drive shaft 122 joumaled therein.The elliptical or circular orbit drive unit is designated generally by117 and the equatorial orientation unit is designated generally by thenumeral 180. The planet 118 may be any of the nine planets and the maindrive unit housing 126 will be inclined at an angle relative to the mainsupport column 120 dependingupon the inclination of the planet's orbitalplane. The drive unit 117 is shown in greater detail in FIG. 5a and theequatorial orientation unit 180 is shown in greater detail in FIG. 5b.

Turning now to FIG. So, we see that the main support column 120 has theshaft 122 joumaled therein by means of bearings 128. The main supportcolumn 120 is interrupted by means of the drive unit cylindrical support124 which may be secured to the cylindrical support column 120 at anydesired angle. Mounted for rotation about the cylindrical support 124 isthe gear assembly housing and systems support 126. Integrally formedwithin the wall of the cylindrical member 124 is a speed changer unit130 having therein a typical epicycle speed changing gearing. The speedchanger unit 130 is provided with an input shaft 132 and output shaft134. A beveled gear 136 is fixed for rotation with the main shaft 122and is in mesh with beveled gear 138 secured to the input shaft 132 ofthe speed charger unit. An elliptical gear 140 is secured on the outputshaft 134 of the speed changer unit and is in mesh with elliptical gear144 secured to stub shaft 142 joumaled for rotation in the housing ofthe speed changer unit 130. Also secured on the stub shaft 142 is acircular beveled gear 146 in mesh with beveled gear 148 which in turn issecured to a hub member 150 joumaled for rotation about the cylindricalsupport column 124 by means of bearings 128. A plurality of drive pins151, only one of which is shown, are secured to the hub 150 for rotationtherewith and are secured at their opposite ends to the gear housing126. Also extending radially outwardly from the hub 150 is a shaft guideand support 152 which slidably receives therein a grooved shaft 154. Astationary cam plate 158 is secured to and completely surrounds thecylindrical support column 124 and is provided in its upper surface withan elliptical gear 160 and in its lower face with a cam groove 176. Agear 156 is slidably mounted on the groove shaft 154 and meshes with theelliptical gear 160 cut in the upper face of the stationary cam 158. Thegear housing 126 is provided with a radially extending hollow portion127 which encompasses the shaft support 152, the shaft 154, and thestationary cam plate 158. Also located within the gear housing extension127 is a second speed changer unit 162 also of the epicycle gear type.The grooved shaft 154 provides the input to the speed changer unit 162and the output shaft 164 is joumaled in the opposite side of the speedchanger unit 162. Secured to the speed changer unit 162 is a camfollower 178 which is adapted to follow the cam track 176 cut in a lowersurface of the stationary cam plate 158. Also secured to the speedchanger unit for movement therewith is a hollow tube member 166 which isslidable in the cylindrical extension arm 168 which is connected to thegear housing extension 127. The output shaft 164 of the speed changerunit 162 is journaled within the hollow tube 166 and is provided at itsopposite end with a beveled gear 184. A spline connection is providedbetween the cylindrical extension 168 of the gear housing and theslidable hollow tube 166. To achieve this end, the cylindrical member168 is provided with an open ended elongated groove 172 and the slidabletube 166 has a spline 174 secured to the surface thereof and which isslidable in the groove 172, as shown in FIG. 6.

in H6. 5b the equatorial orientation unit 180 is shown in greater detailand comprises a drive shaft 182 having a gear 186 on one end thereof inmesh with the gear 184 on the end of the shaft 164. Secured to the outerend of the slidable sleeve 166 is a gear box 185 which houses the gears184, 186. integrally secured with the gear box 185 is the main housing187 for the orientation unit. A shaft support sleeve 188 extendsinwardly of the housing 187 and is concentric with and supports theshaft 182. Secured to the shaft support housing 188 is an epicycle typegear changing unit 190. The gear changer unit 190 is provided with aninput shaft 192 having a gear 194 secured thereto and in mesh with agear 196 secured to the shaft ,182. The output shaft 198 of the speedchanger unit 190 has an elliptical gear 200 secured thereto and in meshwith a second elliptical gear 204 secured to the stub shah 202 joumaledfor rotation in the housing of the speed changer unit 190. Also securedto the stub shaft 202 is the circular beveled gear 206 which is in meshwith a second circular beveled gear 210 secured to a rotatable elongatedtube member 208. The tube member 208 rotates relative to the shaft 182which extends within the tube 208 and the housing 187. Bearings 212 areprovided between the housing 187 and the sleeve 208. The outer end ofthe tube 208 is secured to an additional gear housing 214 which isrotatable therewith. The shaft 182 extends into the housing 214 and hasa gear 220 secured thereto and in mesh with the gear 218 on the end ofthe shafi 2l6 which extends outwardly of the housing 214 and has theplanet 1 18 mounted thereon.

Turning now to a functional description of the elliptical or circularorbit drive unit shown in FIGS. 50 and 5b, we see that rotation of theshaft 122 causes the gear pair 136, 138 to drive the speed changer 130.The period of rotation of the output shaft of the speed changer shallequal the orbital period of the orbiter. Elliptical gears and 144 shalleach have the same eccentricity as the orbit being traversed by theorbiter. Elliptical gears 140 and 144 are mounted on the output shaft ofthe speed changer and the stub shaft 142 to cause the shaft 142 torotate at the same elliptical rate and in phase with the orbital motionof the orbiter. Circular gear 146 is also mounted on shaft 142 andmeshes with gear 148 which rotates and drives the hub 150, the shaftguide and support 152, the shaft 154, and the gear housing 126, 127about the axis of the cylindrical support column 124. Since gear 156 isin mesh with the stationary elliptical gear path 160, the shaft 154 willrotate about its axis. The stationary elliptical gear path shall havethe same eccentricity as the orbit being simulated. Also the ellipticalgear path 160 shall be mounted about the axis of the support tube 124 sothat its foci will correspond to, and be in line with, the perihelion orperigee point of the orbiters orbit. That will cause the gear 156 to bedriven by a variable radius which will counteract the elliptical speedat which the grooved shaft 154 will revolve about the axis of supporttube 124. Therefore, the grooved shaft 154 will rotate about its ownaxis at a constant rate.

The speed changer 162 is driven by the shaft 154 and imparts the correctrotational motion to the extended shafting which drives the equatorialorientation unit and the orbiter 1 18 at its proper rate about itscorrectly oriented equator and/or spin axis.

The cam follower 178 will engage the stationary cam path 176 and causethe orbiters centerpoint to follow its prescribed elliptical path aboutthe center point of the primary, which will be the sun if the orbiter isa planet. This is accomplished by constructing the path of thestationary cam groove 176 with respect to a point on the stationary camplate 158 which is determined by a straight line which is perpendicularto the surface of the plate 158 and intersects the primarys center. Ascam follower 178 traverses its path along the stationary cam 176 thegrooved shaft 154 moves back and forth inside the shaft guide andsupport 152 in accordance with the ellipticity of the orbit beingsimulated. Therefore, speed changer 162 and its extended attachmentsslide back and forth inside the gear assemblys housing and systemsupport 126, 127 and 168. However, gear 156 follows elliptical gear path160 causing the grooved shaft 154 to slide back and forth through thegear 156.

The splined arrangement shown in FIG. 6 enables the shaft 182 to remainperpendicular to the orbit plane. Ifthe orbiting body is a planet ornatural satellite, the equatorial orientation unit 180 causes theequatorial plane of the planet or natural satellite to remain properlyoriented with respect to the orbit plane and vernal equinox as the bodymoves along its orbit and rotates about its spin axis. If the orbitingbody is a spacecraft, the same mechanism can be utilized to cause thespacecraft spin axis to remain properly oriented. With respect to theoperation of the equatorial orientation unit, the gear pair 194,196drives the speed changer 190 to rotate the output shaft 198 of the speedchanger at the same speed as the orbital period of the orbiter.Elliptical gear 200 is mounted on the output shaft of the speed changer190 and meshes with elliptical gear 204 to rotate the circular gear 206and rotate the gear 210 which drives the housing and support member 208in the direction which is counter to the direction the orbiter is movingin its orbit. The housing and support tube 208 makes one completerotation as the orbiter makes a revolution about the center point of theprimary. Elliptical gear pair 200 and 204 shall have the sameeccentricity as the orbit and they shall be mounted to cause the tubularhousing and support 208 to rotate at its maximum rate when the orbiteris passing through the perihelion or perigee point and rotate at theminimum rate when the orbiter is passing through the aphelion or apogeepoint. That will keep the equatorial plane, or spin axis correctlyoriented as the orbiter continually changes orbital velocity inaccordance with the ellipticity of the orbit.

The gear pair 218 and 220 mesh at an angle equal to the inclination ofthe equatorial plane or spin axis of the orbiter. If the spin axis ofthe orbiting body, that is, a planet, natural satellite or spacecraft isperpendicular to the orbit plane, the equatorial orientation unit andgear pair 218 and 220 will not be required.

If the orbiter's same side always faces the center point of the primary,shaft housing and support tube 208 and shaft 216 shall rotate at thesame speed but in opposite directions. The rotation of the moon aboutthe earth is an example of this situation.

The inclination of the orbiter drive unit shown on this drawing isgreatly exaggerated, except for the planet Pluto. Also, if the orbit isabout a planet or the moon, gear pair 136 and 138 can mesh at 90 degreesand the orbital inclination may be achieved by a combination ofangularly oriented drive shafting arrangements somewhat similar to thearrangement shown for the drive of Pluto 114 in FIG. 4, or the planetMars 103 in FIG. 3.

If the orbit of the orbiter is circular, the elliptical gear pairs 140,144 and 200, 204 will not be required and circular gears 146 and 206will be mounted directly to the output shafts of the speed changers 130and 190, respectively. Also, the stationary elliptical gear path 160will be circular, as will the path of the cam follower 178 about itscenter point. The gear assemblys housing and system support 126, 127 and168 can be fixed to sleeve 166 because no sliding action between the twois required.

As pointed out before, the center point of the primary may be the sun'scenter if the orbit is about the sun, or a planets center if the orbitis about a planet, or the moon's center if the orbit is about the moon.

The ellipticity of the various planets about the suns center, or forthat matter, the elliptical orbit of a satellite, either natural orartificial, about the center of a planet, the moon, or anothersatellite, will usually be such that the ellipticity of the orbiter canbe achieved with the cam arrangement and telescopic shafting shown inthe drive arrangement in FIGS. a and 5b However, when the ellipticity ofthe path of an orbiter is extremely large it would be impossible to cuta cam path in the stationary cam plate 158 of the arrangement shown inFIG. 50. Therefore, in order to achieve paths of unusually largeellipticity or to obtain the path of a spacecraft on a flight betweenplanets, it is necessary to resort to the spacecraft telescoping driveunit illustrated in FIGS. 7, 7a and 7 b.

In FIG. 7a, a support column 224 having a flange 225 is secured to alower support column 222 having a flange 223 by means of connectingbolts 226 and nuts 227. A drive shah part 228 is journaled within thesupport column 222 and the drive shaft extension 229 is journaled withinthe support column extension 224. A notched coupling arrangementindicated at 230 enables the drive to be transmitted from shaft 228 toshaft 229. Joumaled for rotation on the support column part 224 is aslip ring unit 232 shown in greater detail and described hereinafterwith respect to FIG. 8. The drive unit comprises a cylindrical supportunit 234 integral with the shaft housing support column 224 and inclinedat any desired angle with respect to the shaft 229 depending upon theangle of the or bital plane of the orbiter. A gear assembly housing andsystem support 236 is journaled about the drive unit cylindrical support234 by means of bearings 238. Mounted on the cylindrical support 234 isan epicycle speed change unit 240 having an input shaft 242 and outputshaft 244. A beveled gear 246 is secured for rotation with the shaft 229and is in mesh with another beveled gear 248 secured for rotation withthe input shaft 242. An elliptical gear 250 is secured to the outputshaft 244 and meshes with a second elliptical gear 254 mounted on shaft252 which in turn is journaled in the housing of the speed change unit240. Also mounted on the stub shaft 252 is a circular gear 256 meshingwith circular gear 258. Gear 258 is mounted for rotation about thesupport column 234 by means of bearings 238 and is formed with a hubmember 260 to which is secured a plurality of drive pins 262 which drivethe gear assembly housing and systems support 236 about the axis of thesupport tube 234.

The housing 236 has a speed changer 274 of the epicycle type mountedtherein for rotation with the housing 236 near the outer extremitythereof. The speed changer 274 is provided with an input shaft 272 andan output shaft 282. The input shaft 272 is splined to enable the gear276 to slide thereon. The inner end of the shaft 272 is secured to a hubmember 268 having a radially extending shaft support tube 270. The hub268 is journaled for rotation relative to the cylindrical support 234.

Secured to the support 234 is a stationary split gear assemblycomprising, a split gear half 264 and a split gear half 266 one on eachside of the gear 276. The bottom surface of the split gear half 264 isprovided with a cam-like gear track 278 and the upper surface of thesplit gear half 266 is provided with a cam-like gear track 280. The twocam-like gear tracks do not overlap each other and the gear 276 isadapted to mesh with first one gear track and then the other as thehousing 236 and the shaft 272 rotate about the axis of the cylindricalsupport column 234. FIG. 10 shows the schematic layout of the gear trackpath of the two split gear halves.

The output shaft 282 of the speed changer 274 is secured to the end of acylindrical drive tube 284 which is journaled in an opening in thehousing 236 by means of bearings 286. The end of the drive tube 284remote from the speed changer 274 is provided with screw threads 288adapted to mesh with the screw threads 292 which extend the entirelength of a second drive tube 290. The drive tube 290 is also providedwith internal threads 294 which mesh with the threads 298 which extendthe entire length of a third drive tube 296. The outermost end of thedrive tube 296 is provided with an internal thread 300 which meshes withthe thread on the screw member 302. The end of the drive tube 290adjacent the speed changer 274 is provided with a circular flange 291having a diameter slightly smaller than the internal diameter of thetube 284, so as to provide a sliding fit therewithin. The end of thedrive tube 296 adjacent to speed changer 274 is also provided with acircular flange 297 having a diameter slightly less than the internaldiameter of the drive tube 290, thereby enabling a sliding fittherewithin. Likewise, the screw member 302 is provided with a circularflange 301 having a sliding fit within the drive tube 296. The screwmember 302 is prevented from rotating by means of a telescopicstabilizer comprising, an outer housing 304 secured to the gear assemblyhousing 236.

to the internal shape of the member 304. A second stabilizer member 308is mounted within the stabilizer member 306 and is provided on one endthereof with a flange member 309 complementary in shape to the internalshape of the stabilizer member 306. A stabilizer rod 310 is mountedwithin the stabilizer member 308 and is provided with a flange 311 onone end thereof complementary in shape to the internal shape of themember 308. The opposite end of the stabilizer rod 310 is provided witha link 312 rigid at one end with the rod 310 and at the other end withthe screw member 302 to prevent rotation of the screw member 302. Anelectric motor 314 is secured to one end of the screw member 302 bymeans of a motor support bracket 316. A drive shaft tube 318 extendsdownwardly from the motor 314 and has the drive shaft 320 joumaledtherein. A spacecraft model 322 is secured to the outermost end of thedrive shaft 320.

The motor at 314 is provided with power by means of a wire 324 which iswound about a spring coil spool 326 which in turn is mounted on abracket 328 which is secured to and depends from the stabilizer member304 and surrounds the bearing 330 in which the outermost telescopic tube284 is journaled. The spring bias spool 326 takes up any excess slack inthe wire 324 as the spacecraft is moved radially inwardly and outwardlywith respect to the central shaft 229. The end of the wire 324 adjacentthe support column 224 is secured to a housing member 232 which isrotatable with respect to the support column 224. Secured to the supportcolumn 224 are a pair of slip rings 334 and 336. 336 is insulated fromthe slip ring hub 334 by means of an insulating ring 337 and the slipring 334 is insulated from the support column 224 by means of aninsulating ring 335. A pair of power supply wires 338 are secured to theslip rings 334 and 336. A pair of brushes 332 and 333 are secured to therotatable housing 232 and bear against the upper surfaces of the sliprings 334 and 336, respectively. The wires 324 have two components eachof which is connected to one of the brush members 332 and 333.

The function of the spacecraft telescoping drive unit is as follows. Thespacecraft telescoping drive unit shown in FIGS. 7a and 7b will be usedto simulate all time-dependent, manned and unmanned space flightmissions which cannot be simulated by the elliptical or circular orbitdrive unit shown in FIGS. 50 and 5b. If the eccentricity of theelliptical orbit to be simulated is so high as to cause the stationarycam 158 in FIG. 5a to be large and therefore impractical, the spacecrafttelescoping drive unit must be used. All planet or natural satelliteorbits can be simulated by the elliptical or circular orbit drive unitshown in FIG. 5, however, either drive unit may be used for the planetPluto. The specific dimensions of a spacecraft telescoping drive unitshown in FIG. 7 is determined by the particular space flight mission tobe simulated.

The shaft 229 causes the gear pair 246 and 248 to drive the speedchanger 240. The period of rotation of the output shaft 244 of speedchanger 240 shall equal the orbital period of the spacecraft. Ellipticalgears 250 and 254 shall each have the same eccentricity as thespacecraft s orbit. Elliptical gears 250 and 254 are mounted on theoutput shaft of the speed changer and the shaft 252 to cause theshaft252 to rotate at the same elliptical rate and in phase with thespacecrafts orbital motion. Circular gear 256 is mounted on shaft 252and drives the gear 258 about the cylindrical support unit 234 as wellas the housing 236 by means of the drive pins 262. As the unit is drivenabout the axis of the cylindrical support unit 234, the gear 276 slidesalong the grooved shaft 272 and meshes with either gear path 278 or gearpath 280 of the split gear to cause grooved shah 272 to rotate and drivethe speed changer 274. Speed changer 274 multiplies the motion of thegear 276 about path 278 or path 280 of the split gear and drives thescrew operated telescoping mechanism which extends or retracts asrequired to keep the spacecraft in its prescribed orbit. The directionof rotation of the grooved shaft 272 reverses when the gear 276 passesfrom path 278 to path 280 or viceversa. This causes the output shaft ofthe speed changer 274 to drive the screw operated telescoping mechanismin the extending or retracting direction as required in the orbital pathof the spacecraft.

The threaded portion of the screw operated telescoping mechanism issimply a series of two or more threaded units, in this case, the tubes284, 290, 296 and the screw member 302. Each one of these with theexception of the outer driving tube 284 will screw in or out dependingupon the direction the driving unit is rotating. For design simplicity,all threads shall be the same distance apart and therefore cause themechanism to extend or retract the same amount for each rotation of thedriving unit 284 regardless of which one of the other units is screwingin or out. The telescoping stabilizer within the member 304 shows across-sectional shape other than round and therefore slides in and outonly. The center unit or rod 310 of the stabilizer is fixed to thecenter screw unit 302 to prevent the screw unit 302 from rotating andthus keep the shaft 320 perpendicular to the sapcecrafts orbital plane.

The electric motor 314 is atached to the end of the center screw unitand imparts rotational motion to the spacecraft. However, if thespacecraft does not require rotational motion about its center of mass,electric motor 314 will not be required and shaft 320 will connectdirectly to the center screw unit.

For earth-lunar and interplanetary space flight missions which requirethe spacecraft to go into orbit about the target planet or naturalsatellite, a spacecraft drive unit and motor arrangement will beattached to the center screw unit and will be constructed in accordancewith the showing in FIG. 9. In FIG. 9. the rigid connecting rod 340would be connected to the outer end of the stabilizer rod 310 and theinner end rigidly connected to the center screw member 302. An electricmotor 342 is secured to the screw member 302 by means of the motorsupport bracket 344. The power supply wires 346 for the electric motor342 may be connected to a slip ring housing on the main support columnin the manner in which the wires 324 are connected to the slip ringassembly, shown in FIG. 8. The output shaft 346 of the motor 342 isconnected to the spacecraft orbiter drive unit 354 which may be the sameas the telescoping unit shown in FIG. 7 or that shown in FIG. 5. On theoutermost end of the drive unit 354 an electric motor 356 is securedthereto by means of a motor support bracket 358. A drive shaft 362 isjoumaled in a drive shaft support tube 360 fixed to the motor 356. Thespacecraft 364 is secured to the outer end of the drive shaft 362 and isadapted to orbit about the target planet or natural satellite shown indotted lines and indicated by numeral 365. The power for the motor 356is supplied by means of wires 350 and 352 across the drive unit 354 bymeans of a slip ring assembly 348 similar to the slip ring assemblyshown in FIG. 8.

To enable the spacecraft to go into orbit about the target planet ornatural satellite, the telescopic drive unit must remain extended at theproper distance. Ordinarily, the gear 276 would leave one split gearhalf, such as gear half 264 and immediately pick up the other split gearhalf 266, and thereby reverse its rotation to retract the telescopicmechanism. Therefore, when it is desired to leave the telescopic driveunit extended to permit the spacecraft to go into orbit about a targetplanet or natural satellite, a different split gear arrangement wouldhave to be utilized which would simply disengage gear 276 at the propertimes. If the mission is round trip, the spacecraft can be adapted toleave the parking orbit at the proper time and return to the departureplanet, in which case,

a further modification of the split gear arrangement would be Irequired. The motor assemblies 342 or 356 may be started and stopped atthe proper times by simply blanking out the unneeded part of the sliprings through which the motor circuit passes.

If the manned or unmanned space flight mission is interplanetary, thespacecraft telescoping drive unit shown in FIG. 7 would be used for thedrive unit 95 shown in FIG. 3 and would be mounted above the suns centeralso as shown in FIG. 3. If the mission is earth-orbital, lunar-orbital,or about a planet or natural satellite only, the spacecraft telescopingdrive unit, if used, will be mounted as illustrated in FIG. 1 with thedrive unit below the center of the primary. That is, the flight path outto the final orbit will not be included.

lf the spacecraft is required to rotate about its center of mass, andthe axis of rotation (spin axis) is not perpendicular to the orbitplane, an orientation unit and gear pair will be required as shown inFIG. 5b. The orbital inclination shown in FIGS. 5a and 7a is greatlyexaggerated except for certain possible space flight missions to Mercuryand Pluto.

Obviously, many modifications and variations of the present inventionare possible in the light of the above teachings, as for example, thearrangement may be non-portable. If is, therefore, to be understood,that within the scope of the appended claims, the invention may bepracticed otherwise than as specifically described.

What is claimed is:

1. An elliptical drive unit comprising a drive shaft, a support, meansfor securing said support at a desired angle with respect to said shaft,cam means secured to said support and defining the desired ellipticalpath, a driven member, drive means for driving said driven member aboutsaid shaft in a closed path and at a variable rate including followermeans engaging said cam means to cause said driven member to follow saidelliptical path, gear track means secured to said support and defining aclosed elliptical path having the same eccentricity as said cam means,gear follower means meshing with said gear track means to rotate saiddriven member about its own axis at a constant rate as said drivenmember is driven around said elliptical path at a variable rate.

2. A drive unit comprising a drive shaft means, a rotatable telescopicdriven means, first gear drive means for driving said driven means aboutsaid drive shaft in a plane which intersects said drive shaft means,second gear drive means for rotating said telescopic driven means aboutits own axis and means for controlling the telescopic movement of saiddriven means; said first gear drive means including elliptical gearmeans for driving said driven means about said shaft at a variablespeed.

3. A drive unit according to claim 2 wherein said second gear drivemeans comprises stationary gear track means and said driven meansincludes extensible screw means disposed concentrically about a centraltelescopic screw rod, gear follower means secured to said extensiblescrew means and meshing with said gear track means whereby rotation ofsaid driven means about said drive shaft means causes said gear followermeans to rotate said extensible screw means to move said driven meansradially with respect to said drive shaft means while preventingrotation of said central telescopic screw rod about the axis of saidscrew means.

4. A drive unit according to claim 3 wherein said gear track meanscomprises a split gear, each gear portion containing half of said geartrack, said split gear track means being so constructed and arrangedthat when said gear follower means is in contact with one half of saidsplit gear track said screw means will be rotated in one direction tomove said driven means in one radial direction with respect to saiddrive axis and when said gear follower means is in contact with theother half of said split gear track said screw means will be rotated inthe opposite direction to move said driven means in the opposite radialdirection.

5. A drive unit according to claim 3 wherein said extensible screw meansincludes a plurality of hollow telescopic screw members disposed aboutsaid central telescopic screw rod and means preventing rotation of saidscrew rod; additional driven means being connected to the end of saidrod remote from said drive shaft means and the outermost of said hollowscrew members being connected to said gear follower means.

6. A drive unit according to claim 5 wherein said additional drivenmeans comprises auxiliary drive means secured to said screw rod forrotating said additional driven means about its axis of rotation at aconstant speed.

1. An elliptical drive unit comprising a drive shaft, a support, meansfor securing said support at a desired angle with respect to said shaft,cam means secured to said support and defining the desired ellipticalpath, a driven member, drive means for driving said driven member aboutsaid shaft in a closed path and at a variable rate including followermeans engaging said cam means to cause said driven member to follow saidelliptical path, gear track means secured to said support and defining aclosed elliptical path having the same eccentricity as said cam means,gear follower means meshing with said gear track means to rotate saiddriven member about its own axis at a constant rate as said drivenmember is driven around said elliptical path at a variable ratE.
 2. Adrive unit comprising a drive shaft means, a rotatable telescopic drivenmeans, first gear drive means for driving said driven means about saiddrive shaft in a plane which intersects said drive shaft means, secondgear drive means for rotating said telescopic driven means about its ownaxis and means for controlling the telescopic movement of said drivenmeans; said first gear drive means including elliptical gear means fordriving said driven means about said shaft at a variable speed.
 3. Adrive unit according to claim 2 wherein said second gear drive meanscomprises stationary gear track means and said driven means includesextensible screw means disposed concentrically about a centraltelescopic screw rod, gear follower means secured to said extensiblescrew means and meshing with said gear track means whereby rotation ofsaid driven means about said drive shaft means causes said gear followermeans to rotate said extensible screw means to move said driven meansradially with respect to said drive shaft means while preventingrotation of said central telescopic screw rod about the axis of saidscrew means.
 4. A drive unit according to claim 3 wherein said geartrack means comprises a split gear, each gear portion containing half ofsaid gear track, said split gear track means being so constructed andarranged that when said gear follower means is in contact with one halfof said split gear track said screw means will be rotated in onedirection to move said driven means in one radial direction with respectto said drive axis and when said gear follower means is in contact withthe other half of said split gear track said screw means will be rotatedin the opposite direction to move said driven means in the oppositeradial direction.
 5. A drive unit according to claim 3 wherein saidextensible screw means includes a plurality of hollow telescopic screwmembers disposed about said central telescopic screw rod and meanspreventing rotation of said screw rod; additional driven means beingconnected to the end of said rod remote from said drive shaft means andthe outermost of said hollow screw members being connected to said gearfollower means.
 6. A drive unit according to claim 5 wherein saidadditional driven means comprises auxiliary drive means secured to saidscrew rod for rotating said additional driven means about its axis ofrotation at a constant speed.